Treatment of hydrocarbons



Dec. 23; 1941. A. R. GOLDSBY 2,267,458

TREATMENT OF HYDROCARBONS Filed Aug. 18, 1958 HY DROCARBON CHARGE ACID CHARGE.

ALKYLATION .USED

ACID

HYDROC'ARBON OIL v T l ACiD I TREAT-ED on. TREATMENT T ACID RECOVERY RECOVERED ACID ARTHUR R.GOLDSBY INV TOR g, T MM &,,

ATTORNEYS Patented Dec. 23,1941

TREATMENT or nrnnocannons Arthur R. Goldsby, Beacon,N. Y., assignor, by mesne assignments, to The Texas Company, New York, N. ,Y., a corporation of Delaware Application August 18,1938, Serial No. 225,555

. 8 Claims.

This invention relates to the refining of hydrocarbon oils by acid treatment and-has to do particularly with the utilization of a used orspent acid, formed by previously alkylating isoparafiin hydrocarbons with olefin hydrocarbons in the presence of sulfuric acid, as the acid treating reagent.

In the alkylation of low boiling isoparaflins, such as isobutane and isopentane with olefins, for example normally gaseous olefins or poly- The sludge acid separated from the treating operation is subjected to conventional acid recovery methods whereby a restored acid, suitable mers thereof, in the presence of sulfuric acid to I produce branch chain saturated gasoline hydrocfabout 93% sulfuric acid, by an unsaturated carbons of-high antiknock value, the acid gradually becomes spent and ineffective as a catalyst for suchpurpose.

The spent acid comprises mainly sulfuric acid and organic carbon containing materials, prin cipally as hydrocarbon compoundsyand differs from ordinary Sludge'acid obtained from the acid treatment ofhydrocarbon oils in that the water content is ve'ry'l'ow. The organic carbon" containing materials may run from 1 to and usually about 4 to 10%; While the acid is no longer effective as an alkylation catalyst, has been found that the acid can'be usedadvantageously for the acid treatment of, hydrocarbon oils to refine the oil by removing undesir-- able constituents therefrom, such as gums, resins, sulfur compounds and the like. i

The oils that may be treated according to the invention are any hydrocarbon oilsordinarily subjected to refining by acid treatment. It is intended that petroleum oils, such as distillates, including lubricating oil, kerosene and naphtha or gasoline may be used. The invention is particularly applicable to the treatment of cracked distillates or cracked gasoline wherein the distillate is ordinarily givenan acid dosage of about 3 to 5 pounds and the acid treated oil, after the separation of the acid sludge, neutralized and rerun by steam distillation. The amount of used acid required for acid treatment is ordinarily in the same proportion by weight as that used in the case of new acid. In some cases, however, it may be desirable to use spent acid in an amount equivalent to new acid on a percentage acidity basis; or the spent acid may be fortified with a stronger acid, such as 98% acid, or fuming acid to bring the acidity up to the equivalent of new acid and then a dosage, equivalent by weight to that usedin the treatment with the new acid, used.

Any well known or preferred type of acid treating equipment may be used and the confor reuse in the alkylation operation may be obtained. 1 1 i The accompanying drawing is a flow chart showing the operation of the process.

- An example will now be given of the process.

of the invention as applied to the use of spent acid derived from an alkylation operation in which isobutane was alkylated, in the presence hydrocarbon fraction of cracking still gases containing C3 and C4 hydrocarbons, using afresh feed ratio of isobutane to olefins of about' 3zl, a

ratio by weight of acid to olefins in the feed of about 0.6:1, and a temperatureof about 65 F. The used acid 'fromthe operation analyzed as follows: Percent HzSOrby titration; 86.6 Percent H2804 (CH2), free-.. 91.1

Percent organic calculated as carbon 0.48 Percent organic calculated as (CHzhh--- 5.04 Specific gravity at 60 F 1.702

A cracked naphtha having an initial boiling point of 113 F. and an end point of 402 F. was treated with the used acid. The results obtained, as compared with those fromtreating the same naphtha without any acid and with fresh acid are shown in the following table. The.

oils in each case were neutralized, steam distilled and sweetened.

Spent The spent acid from the acid treating operation may be run to the acid recovery plant wherein it is restored to desired concentration and reused inthe alkylation operation.

The use of the spent alkylation acid in the refining of oils by-acid treatment may produce a refined oil of improved properties, such as color. sulfur and gum content, and less sludge formation and acid treating loss, as compared to ventional methods of acid treatment employed. normal acid treatingoperations.

Obviously many modifications and variations of the invention as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A process for refining hydrocarbon oils containing objectionable sulfur, color and gumforming compounds, which comprises subjecting the oil to treatment with used sulfuric acid, which has been obtained from the alkylation of isoparaffins with olefins in the presence of strong sulfuric acid, whereby such objectionable compounds are substantially removed.

2. A process for the refining of hydrocarbon distillates containing undesirable sulfur, color and gum-forming compounds, whichcomprises treating the distillate with used sulfuric acid, which has been obtained from an alkylation operation wherein isoparafflns are alkylated with olefin hydrocarbons in the presence of strong sulfuric acid as a catalyst, whereby such undesirable compounds are substantially removed.

3. A process for the refining of light petroleum distillates to remove sulfur, color and gumforming compounds which comprises contacting the distillate with used sulfuric acid, which has been obtained by alkylating low boiling isoparaffins with olefins in the presence of strong sulfuric acid as the catalyst, said used acid containing about 1 to 20% of organic material soluble therein, and separating the acid sludge from the treated distillate.

. 4. A process for the refining of cracked hydrocarbon distillates to remove sulfur, color and gum-forming compounds, which comprises contacting the distillate with used sulfuric acid, which has been formed in the alkylation of low boiling isoparaflins with olefins in the presence of strong sulfuric acid as a catalyst, said used acid consisting essentially of sulfuric acid and organic material soluble therein, and separating the acid sludge from the treated'oil.

5. A process which comprises subjecting an alkylation acid containing organic material soluble therein for the acid treatment of petroleum distillates to remove color and gum-forming compounds therefrom.

6. A process which comprises alkylating low boiling isoparaflins with normally gaseous olefins and polymers thereof in the presence of strong sulfuric acid, whereby saturated high antiknock gasoline hydrocarbons are formed, separating the used acid containing organic material soluble therein from the reaction products, treating a petroleum distillate with said used acid containing said soluble organic material to refine the distillate by removing sulfur, color and gumforming compounds therefrom, separating a sludge acid from the last mentioned treating operation, recovering a strong sulfuric acid of alkylation strength from said sludge acid and returning the recovered acid to the alkylation operation.

7. In the refining of hydrocarbon oil containing undesirable sulfur, color and gum forming compounds, the process which comprises treating the oil with preformed acid sludge, derived from an alkylation operation wherein an isoparafiin is alkylated with an olefin hydrocarbon in the presence of sulfuric acid as a catalyst, whereby such undesirable compounds are substantially removed from the oil. 1

8. In the refining of cracked naphtha containing undesirable sulfur, color and gum forming 

